<!DOCTYPE html>
<html>
<head>
<link rel="author" href="mailto:sammy.gill@apple.com">
<link rel="help" href="https://drafts.csswg.org/css-box-4/#margin-trim-grid">
<meta name="assert" content="spanning grid item adds columns to implicit grid and should be trimmed">
<style>
grid {
    display: grid;
    grid-template-columns: repeat(2, auto);
    outline: 1px solid black;
    margin-trim: inline-end;
}
item {
    display: block;
    height: 50px;
}
.span-three {
    grid-column: span 3;
}
.locked-position {
    grid-row: 1;
    grid-column: 2;
}
item:nth-child(1) {
    background-color: aqua;
    margin-inline-end: 10px;
}
item:nth-child(2) {
    background-color: blueviolet;
    margin-inline-end: 30%;
}
item:nth-child(3) {
    background-color: blue;
    margin-inline-end: -30px;
}
item:nth-child(4) {
    background-color: coral;
    margin-inline-end: 10px;
}
</style>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/check-layout-th.js"></script>
</head>
<body onload="checkLayout('grid > item')">
    <div id="target">
        <grid>
            <item class="locked-position" data-expected-margin-right="10"></item>
            <item class="span-three"></item>
        </grid>
    </div>
</body>
</html>
